Delayed opening poppet valve for steam engines



June 9, 1953 H. M. ARNOL 2,641,438

DELAYED OPENING POPPET VALVE FOR STEAMENGINES Original Filed Aug. 17,1945 El l z l 7 Inventar ,my n. le By Patented June 9, 1.953

DELAYED OPENING PoPPE'r VALVE FOR STEAM ENGINES Harry Arnold,Golden,Colo. r a Original application August 17, 1945, Serial No.

1946, Serial No. 660,979

This invention relates to a special form of puppet-valve mechanismintended primarily for use in steam engines utilizing very highlylsuperheated steam or other hot .gases working as steam. Thisapplication is a divisional application containing subject matterillustrated but not claimed in my Patent No. l2,464,112, granted March8, 1949, on Cylinder Headfor Superheated Steam Engine. v

The general object of the invention is to provide a simple and verystrongly built poppet valve mechanism and oscillating cam similar to thevalve mechanism of internal combustion engines but having specialproperties making it very effective for uid admission valves insuperheated steam engines. Y

The present practice in puppet-valves now used in steam engines is topop the valve open very `quickly and let it seat quickly. If the engineoperates at high piston speed, as is the case with modern engines, thevalve is lifted and seated so quickly the inertia of the valve andrelatedparts is a very detrimental factor. Poppet-valve mechanisms ofthis type are very noisy at high speed because of the hammer-like blowsset up 101mm. (cisti-132i in the mechanism by the very. sudden openingand closing of the valve. n

I provide a cam and poppet-valve assembly so constructed that the cam i,lifts the valve very gradually andallows it to seat again in a verygradualmanner. In order to obtain efficiency in a steam engine the valvemust open and close the valve port very quickly to avoid undueresistance to the flow of steam entering the cylinder. The labyrinthseal in common use in steam turbines has proven of great value where twosurfaces are not allowed to touch while in motion. I apply the labyrinthseal to rings or skirts provided under the valve heads so the steam willnot be admitted into the cylinder until vthe cam has accelerated theValve to its position of maximum velocity. When the valve closes, itinterrupts the how of steam entering the cylinder at its point ofmaximum velocity.

A small amount of steam will leak past the labyrinth seal so. provided.Ithas been found in steam turbines that the steam thus: lost is verysmall as compared with the great volume of steam used to .drive theturbine. Likewise, the steam escaping into the cylinder of the engineduring the very small interval of time the seal is in use will benegligible.

Referring to the accompanying drawings wherein like numbers denote likeparts throughout; the features of the invention are explained detail.- y

and this skirt fitsy .inside the .valve .port with Divided and thisapplication April 10,

Figure 1 is a fragmentary longitudinal sectional view of a cylinderhaving a high'V lift Vvunbalanced single beat puppet-valve commonly usedin internal combustion engines. but provided with the cam and labyrinthseal. Y

Figure 2 is a side elevationalv View: of a.'` valve head showing theaddition of the' skirted' part which is the most simple labyrinth seal.

Figure 3'.l is a diagrammatic view Aofj the` cam and follower and showsthe way 'the cam imparts the desired motion to the follower'. a

Figure 4 is a fragmentary cross-sectional view of the cam, cam shaft,bearing and cylinder taken on the line 4-4 of Figure 1.

Figure 5 is a fragmentary longitudinal sectional view of a cylindervprovided with a high lift single beat balanced poppet-valvewith a hatseat having the cam and labyrinth seal applied to it.

Figure 6 is a fragmentary r'longitudinal sectional view of a cylindershowing the application of the cam and rlabyrinth seal to a doubleported tubular Valve.

Figure 7 is a greatly enlarged fragmentary view of the double portedtubular valve showing the application of the labyrinth seal to the innervalve seat, and

Figure 8 is a modification thereof.

In these drawings the memberv lis a specially made oscillating cam soconstructed and located that it can be used to actuate lone `valve as ina single acting engine or two valvesas in a double acting engine. Thedouble acting engine is illustrated in detail in my Patent No.2,464,112.

Referring to Figure 3 it will be seenA that the cam l first contactslthe follower 2 at the point A which'is nearly in line with the center ofthe cam shaft l2 and at the beginning of decline ,tof ward the centerline R of said cam.l Atthis point the velocity of contact is Very slowand the lifting power of the cam is very greatso that the valve head 3,of Figure 2, is started fromre'st with very little impact and with verylittle strain on the accompanying valve mechanism. The face of the cam Imay be a curve, or a combination of curves of varying radii. This makespossible the most `desirable acceleration of thevalve head 3 from itspoint of rest at A to its point of maximum velocity at the point B.During the movement ofthe cam l from A to B the valve u head 3 will belifted a distance S from its seat.

It is during this slow movement of the valve head 3 that admission ofsteam tothe cylinder is not desired. vA cylindrical skirt 5 ,equal inwidth t0 the distance S is applied to the valve head 3 valve extends.

a very small clearance so no rubbing contact is involved. The smallclearance thus provided is the most simple form of the labyrinth sealand When the clearance is small the steam leaking through becomes a verysmall quantity. The port a is formed in a valve sea-.tl member 5b.

At the point B the valve head' 3 is traveling at its greatest velocityand the edge of the skirt 5 passes the edge of the valve port 5a, givinga quick opening of the port. From B to C the cam comes to rest and thevalve head 3 is then its fun open position. Next the cam I returns toposition B and the valve spring and, steam pressure cause the valve head3 to follow the follower 2 and cam I so they are traveling at theirmaximum velocity again when the skirt 5 on the valve head 3 enters theport 5a and interrupts the iiow of steam into the cylinder. From B- to Athe cam I checks the velocity of the valve head 3 so that valve. head 3engages the seat 5b when traveling very slowly.

In Figure 4 the simple and sturdy construction` ofthe cam I, follower 2and cam shaft I2 can be seen. Bearing inserts I3 are held in position bythe cap I4 which in turn is held in position on the cyliiiderv Il by thebolts I5. In very large engines the cam shaft I2 can be made to extendthrough the cam I so another bearing I3, lll and I5, shown' in dottedlines, can be used to give additional strength and bearing surface. Thedrive arm and pin I6 for the shaft I 2 may be made 'as part of the shaftI2. A bolt and washer 22 hold the driving rod on the pin I 6.

Figure 6 shows the application of the cam I and labyrinth seal to adouble beat tubular valve 3a. The valve 3a engages the seat member 5c atits outer end while the inner end extends into the valve seat member Iia distance which is approximately equal to the travel of the cam I fromits point of contact with the follower 2 at A to the point B, see Figure3. A skirt 5d is also provided at the outer end of the valve 3a. Thefollower 2 has a Working iit in a chamber made in a part of the cylinderblock IT. The valve spring 'l holds the valve 3a in closed position andis secured to the valve stem 4 by the stem key 8. The hot steam, orother gases Working as steam, enter the valve chest I0 through the pipe9. A special metal seal II may be used at the junction of the valvechest I0 and the cylinder head I8.

Figure 7 shows the details of the labyrinth seal applied to the innerend of the valve 3a by providing a channel Se in the vaiveseat member 6into which the tapered inner edge I5b of the In larger valves the sealmay be made more effective by using several concentric channels 6d inthe valve seat for receiving circular ribs 3c on the valve, as shown inFigure 8. Figure 8 is the true labyrinth seal as used in steam turbines.

In'double ported valves the common practice is to use a exible seat ateither the outer end of the valve or at the inner end. When very hightemperatures are employed, the Wear of such a vaive seat assemblybecomes too great for practical use. When'the labyrinth seal is used thevalve 3a does not contact the seat 6. When Vthe valve 3a and seat 6 arecold the clearance at thebottomy of the grooves will be considerable, upto 1/4" or more in large valves.v After the valve 3a and seat 6 heat upto their normal running temperature valve 3a will extend deeper 1 intethe seat so that a very small clearance will exist. If the valve 3d andseat 6 are 'made l l, .of the same kind of material the expansion 75said block and having one end thereof projecting radially will beapproximately the same so the flanges of the seal Will not bind on thevalve flanges.

Figure 1 shows the cam I and skirt 5 applied to a single beat high liftunbalanced poppet-valve Rythe .same as that of Figure 2. The valve seat5b is a tapered seat to engage the beveled edge of the valve 3. A valvestem guide 6a. is provided for the valve stem 4 to slide in. The valvestems 4 have annular grooves 4a for collecting oil or moisture for a.seal.V The valve seat 5b is pressed into a flange made as a part of thecylinder II.

When very high temperatures are to be used, the circulating systemexplained and illustrated in my Patent lblo.v 2,464,112 will keep thevalve guides 6, 6ar and 6b and the valve stems 4 at a low temperature sooil or moisture will remain in the grooves around the stems 4. Portionsof the valve mechanism may be insulated to avoid heat 4lossesA as willbe seen in my Patent No. 2,192,000 granted March 19, 1940, onSuperlxeated Steam Engine. y

Figure 5 shows thecam I and skirt 5e applied to ahigh lift single beatvpoppet-valve of the balanced type. The valve 3h engages the seat 5c andhas a at flange 5f projecting from the valve at right angles to thecutsoff skirt 5e for er1- gaging the valve seat 5c.

A small piston I9 is 'fitted Wtih'rings 20 that have a working tin' asmall cylinder 22 in the main cylinder Vblock IT. 'The valve guide Gbisshort. A passageway 2f is provided for steam or other gases underpressure to enter behind the piston I9 so that Aa large part of thepressure on the valve 3b willv be balanced 01T. The cam I and relatedmechanism can be made smaller and lig-her because less Work is requiredto open the valve.

In this valve assembly the cooling system illustrated in my Patent o.2,464,112 is very important as a means of preventing overheating of thepiston I9, rings 20,valve guide Gb and valve stem 4.

In Figure 3 it wiil be seen that cam I swings through an arc on eachside of the vertical center lineR Without disengaging the valve 3'. Whenthe Well-known reversing link and combination motions are used and thelink is in mid-position, a` small amount of motion is imparted to thecam I but not enough to disengage the valve 3. As the link is movedtoward either extremity the cam I reaches its full swing atV C. Thismakes possible any desired opening of the valve from nothing to fullopen in either direction of rotation of the engine.

In stationary-'engines designed to run continuously in one direction ofrotation, the well-known fly-wheel governor and single variableeccentric will give the same results.- When the eccentricity isdecreased by the governor the valves will open less or not at all.

It is to be understood that changes may be made in the combination andarrangen'ientV of the several parts provided that such changes fallWithin the scope of the appended ciaim.`

Having described my invention, what is claimed as new is:

Poppet valve mechanism for anv engine including a cylinder block havinga cylinder therein, said valve mechanism being supported by the blockand comprising a valve stem mounted for axial reciprocation within anelongated valve stem guide member, said stem being provided with aseries of axially spaced oil collecting grooves, said guide member beingsupported in centrally within a cylindrical open ended recess in theblock, a coil spring disposed Within said recess in encircling relationto said stem and said one end of the guide member and having itsopposite ends reacting upon the end Wall'of said recess and an abutmenton said stem for yieldably urging the stem toward the open end of saidrecsss, a cylindrical cup-shaped follower member disposed within saidrecess and including an end Wall engaging the corresponding end of saidstem and exposed through the open end of said recess and a cylindricalwall within which the adjacent ends of said valve stern and said springare disposed, a follower actuating `carn supported on a shaft Whose axisis disposed laterally of the axis of said stem and at right anglesthereto and which shaft is oscillatably supported by said block, saidcam having a convex surface engageable with said follower end Wall andoperative to axially move said stem against the action of said spring, avalve head seat member supported bysaid block in concentric relation tosaid stem, said valve seat member being provided with a circular valvehead seating face on the outer lateral side thereof and a fluidadmission port in said seat member having a cylindrical wall extendingdirectly inwardly from said seating face and said valve stem extendablethrough said port, a v-alve 'head on the opposite end of said stemhaving a seating face for cooperating with the seating face on said seatmember, a skirt projecting directly inwardly from said seating face andhaving an outer cylindrical surface adapted to be disposed Within and insubstantial engagement with said cylindrical Wall in the seatedposi-tion of said valve head, and said skirt being of a length less thanthe range of movement of said head between its seated position and itsmaximum open position.

HARRY M. ARNOLD.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 201,352 Little Mar. 19, 1878 638,564 Davies Dec. 5, 1899847,086 Lentz Mar. 12, 1907 1,322,035 Madigan Nov. 18, 1919 1,500,342Smith July 8, 1924 1,509,862 Edick Sept. 30, 1924 1,695,726 Woolson Dec.18, 1928 2,395,633 Livers Feb. 26, 1946

